Microstructural development of a gas-atomized and hot-pressed super-α2 alloy

A variety of heat treatments have been employed to explore the microstructure in Ti-25Al-10Nb-3V-1Mo alloy prepared by gas atomization and hot pressing. These treatments include quenching by oil cooling and water cooling and aging at temperatures between 530 degrees C and 950 degrees C. Quenching transformations from the beta-phase field include the formation of O phase in oil quenching and beta (disordered) + O phase in water quenching. The metastable beta phase decomposes into O + ''omega'', O, or alpha(2) + beta(0)/B2 phase when the as-quenched alloy is aged at various temperatures. By comparing the selection area diffraction patterns, it has been found that the ordered omega phase in the alloy studied in this article is distinct in structure to the ''omega type'' (P3m1) and B8(2) phase which are formed in the parent matrix of the ordered beta(B2,D0(3)) phases. It has also been shown by X-ray diffraction (XRD) analyses that the lattice parameters of the as-aged O phase do not remain constant in the alloy at various temperatures.